Rainbow Birthday Cake

This rainbow birthday cake is great for a kid's birthday party!

Prep Time:
30 mins
Cook Time:
35 mins
Additional Time:
1 hrs
Total Time:
2 hrs 5 mins
1 3-layer cake


  • 1 cup butter, softened

  • 1 ¾ cups white sugar

  • 4 eggs

  • 2 teaspoons vanilla extract

  • 2 ¾ cups all-purpose flour

  • 2 teaspoons baking powder

  • ¾ teaspoon baking soda

  • 1 ¼ cups buttermilk

  • red, yellow, and blue food coloring

Butter Icing:

  • 1 cup unsalted butter, softened

  • 1 pinch salt

  • 4 cups confectioners' sugar

  • ¼ cup heavy cream

  • ½ teaspoon vanilla extract

  • orange, green, and purple food coloring

Fluffy Icing:

  • 1 cup white corn syrup

  • 2 egg whites

  • ¼ teaspoon cream of tartar

  • 1 teaspoon vanilla extract


  1. Preheat the oven to 350 degrees F (175 degrees C). Grease the sides of three 9-inch round cake pans; line bottoms with parchment paper.

  2. Beat butter with sugar in a large bowl using an electric mixer until fluffy. Add eggs, 1 at a time, beating well after each. Mix in vanilla extract. Combine flour, baking powder, and baking soda. Stir into butter mixture alternately with buttermilk, making 3 additions of flour mixture and 2 of buttermilk.

  3. Divide batter among 3 bowls. Tint one bowl red, one yellow, and one blue. Scrape each into one of the prepared pans and smooth the tops.

  4. Bake in the preheated oven until a toothpick inserted into the centers comes out clean, about 30 minutes. Cool cakes on a wire rack for 15 minutes. Run a table knife around the edges to loosen. Turn out onto a cooling rack. Peel off parchment paper and let cool for 30 minutes before frosting.

  5. Beat unsalted butter and salt together in a large bowl until smooth. Beat in confectioners' sugar alternately with cream, making 3 additions of sugar and 2 of cream. Mix in vanilla extract. Divide butter icing among 3 bowls. Tint one orange, one green, and the other purple.

  6. Place red cake layer on flat serving plate; spread top with orange icing. Top with yellow layer; spread green icing on top. Add the blue layer and cover it with purple icing. Refrigerate for 30 minutes or until icing is firm.

  7. Place corn syrup in a saucepan and bring to a boil. Meanwhile, beat egg whites and cream of tartar together until frothy in a heat-proof bowl set over a pan of simmering water. Beat in the corn syrup in a thin, steady stream until stiff peaks form. Remove from heat and beat in vanilla. Top cake with fluffy icing.

Cook's Note:

Use milk instead of cream if you like.

Nutrition Facts (per serving)

590 Calories
26g Fat
87g Carbs
5g Protein
Nutrition Facts
Servings Per Recipe 16
Calories 590
% Daily Value *
Total Fat 26g 33%
Saturated Fat 16g 80%
Cholesterol 113mg 38%
Sodium 272mg 12%
Total Carbohydrate 87g 32%
Dietary Fiber 1g 2%
Total Sugars 59g
Protein 5g
Vitamin C 0mg 1%
Calcium 79mg 6%
Iron 1mg 7%
Potassium 96mg 2%

* Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.

** Nutrient information is not available for all ingredients. Amount is based on available nutrient data.

(-) Information is not currently available for this nutrient. If you are following a medically restrictive diet, please consult your doctor or registered dietitian before preparing this recipe for personal consumption.

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